card_key_provider: add PostgreSQL support

The Card Key Provider currently only has support for CSV files
as input. Unfortunately using CSV files does not scale very well
when the card inventory is very large and continously updated.
In this case a centralized storage in the form of a database
is the more suitable approach.

This patch adds PostgreSQL support next to the existing CSV
file support. It also adds an importer tool to import existing
CSV files into the database.

Change-Id: Icba625c02a60d7e1f519b506a46bda5ded0537d3
Related: SYS#7725

pySim/card_key_provider.py

@@ -36,6 +36,7 @@ from pySim.log import PySimLogger
 import abc
 import csv
 import logging
+import yaml
 
 log = PySimLogger.get("CARDKEY")
 
@@ -159,6 +160,7 @@ class CardKeyProviderCsv(CardKeyProvider):
                 csv_filename : file name (path) of CSV file containing card-individual key/data
                 transport_keys : (see class CardKeyFieldCryptor)
         """
+        log.info("Using CSV file as card key data source: %s" % csv_filename)
         self.csv_file = open(csv_filename, 'r')
         if not self.csv_file:
             raise RuntimeError("Could not open CSV file '%s'" % csv_filename)
@@ -186,6 +188,69 @@ class CardKeyProviderCsv(CardKeyProvider):
             return None
         return return_dict
 
+class CardKeyProviderPgsql(CardKeyProvider):
+    """Card key provider implementation that allows to query against a specified PostgreSQL database table."""
+
+    def __init__(self, config_filename: str, transport_keys: dict):
+        """
+        Args:
+                config_filename : file name (path) of CSV file containing card-individual key/data
+                transport_keys : (see class CardKeyFieldCryptor)
+        """
+        import psycopg2
+        log.info("Using SQL database as card key data source: %s" % config_filename)
+        with open(config_filename, "r") as cfg:
+            config = yaml.load(cfg, Loader=yaml.FullLoader)
+            log.info("Card key database name: %s" % config.get('db_name'))
+            db_users = config.get('db_users')
+            user = db_users.get('reader')
+            if user is None:
+                raise ValueError("user for role 'reader' not set up in config file.")
+            self.conn = psycopg2.connect(dbname=config.get('db_name'),
+                                         user=user.get('name'),
+                                         password=user.get('pass'),
+                                         host=config.get('host'))
+            self.tables = config.get('table_names')
+            log.info("Card key database tables: %s" % str(self.tables))
+            self.crypt = CardKeyFieldCryptor(transport_keys)
+
+    def get(self, fields: List[str], key: str, value: str) -> Dict[str, str]:
+        import psycopg2
+        from psycopg2.sql import Identifier, SQL
+        db_result = None
+        for t in self.tables:
+            self.conn.rollback()
+            cur = self.conn.cursor()
+
+            # Make sure that the database table and the key column actually exists. If not, move on to the next table
+            cur.execute("SELECT column_name FROM information_schema.columns where table_name = %s;", (t,))
+            cols_result = cur.fetchall()
+            if cols_result == []:
+                log.warning("Card Key database seems to lack table %s, check config file!" % t)
+                continue
+            if (key.lower(),) not in cols_result:
+                continue
+
+            # Query requested columns from database table
+            query = SQL("SELECT {}").format(Identifier(fields[0].lower()))
+            for f in fields[1:]:
+                query += SQL(", {}").format(Identifier(f.lower()))
+            query += SQL(" FROM {} WHERE {} = %s LIMIT 1;").format(Identifier(t.lower()),
+                                                                  Identifier(key.lower()))
+            cur.execute(query, (value,))
+            db_result = cur.fetchone()
+            cur.close()
+
+            if db_result:
+                break
+
+        if db_result is None:
+            return None
+        result = dict(zip(fields, db_result))
+
+        for k in result.keys():
+            result[k] = self.crypt.decrypt_field(k, result.get(k))
+        return result
 
 
 def card_key_provider_register(provider: CardKeyProvider, provider_list=card_key_providers):